Process control systems utilize a variety of field devices to control process parameters. Fluid regulators are commonly distributed throughout process control systems to control the pressures of various fluids (e.g., liquids, gasses, etc.). Fluid regulators are typically used to regulate the pressure of a fluid to a substantially constant value. Specifically, a fluid regulator has an inlet that typically receives a supply fluid at a relatively high pressure and provides a relatively lower and substantially constant pressure at an outlet. For example, a gas regulator associated with a piece of equipment (e.g., a boiler) may receive a gas having a relatively high pressure from a gas distribution source and may regulate the gas to have a lower, substantially constant pressure suitable for safe, efficient use by the equipment.
Fluid regulators typically control the flow and pressure of fluid using a diaphragm having a set or control pressure force applied to one of its sides via a bias spring. The diaphragm is also operatively coupled directly or via a linkage (e.g., a lever) to a valve disk that is moved relative to an orifice of a seat ring that fluidly couples the inlet of the regulator to its outlet. The diaphragm moves the disk in response to a difference between the outlet pressure and the set or control pressure to vary the flow restriction provided by the disk to achieve a substantially constant outlet pressure, which provides a balancing force to the other side of the diaphragm that is equal or proportional to the set or control pressure.
Different markets around the world often require different combinations of fluid regulator operational and/or performance characteristics. In particular, a desired or required combination of performance or operational characteristics such as, for example, the type of trim, regulator diaphragm assembly action (e.g., direct acting, pressure loaded, pilot operated, etc.), overpressure protection, pressure registration (e.g., internal, external, dual internal/external, etc.) can vary widely across the global marketplace. However, many of the desirable or required combinations of performance or operational characteristics are exclusive of one another and, as a result, many fluid regulator manufacturers provide a number of differently designed regulator product families, each or which is specifically configured to suit the particular needs of a different global market. Such an approach to satisfying global market needs results in manufacturers having to produce and support a large number of diverse products, which is logistically difficult and costly.